The instant invention relates to the devices on-board an aircraft that allow the physical passing of an object through the aircraft belly, such as a cylindrical tube, from a position inside the craft to one outside.
In many instances, when aircraft are patrolling the oceans, it may be necessary to launch objects, such as sonobuoys or flares, from an inner compartment, through the aircraft's underside skin, to the outside. Some aircraft are fitted with a internal pressurized launch chutes that extend from just inside the cabin area to a position adjacent to the inside of the aircraft skin. A mechanically-operated door, acting in place of the skin, moveably covers and uncovers the opening and allows the object to be fired by either hydraulic or pneumatic means, into the surrounding atmosphere.
Of course, during this time, the aircraft is flying at a predetermined altitude and airspeed and there can be quite a lot of turbulent airflow adjacent the aircraft's skin or within the area adjacent the ends of the launch tubes. In designing the area to hold the launch chutes, a selected amount of space between the mechanical door and the end of a launch container was chosen to aid in the construction of the aircraft. At the time of aircraft design, the approximate size of the buoy, such as a sonobuoy, was known (it was a 3 foot long tubular object) and it was determined that this size would launch without difficulty. The container was long enough so that as the lead end of a buoy started into the cavity between the aircraft skin and the end of the container, the trailing end of the buoy was still positioned in the launch container, thus ensuring that the total length of the buoy would not be jostled out of position and would pass on through without mishap. As times progressed, the size of the sonobuoy decreased to a point where the buoy was now physically small enough so that it could get caught inside the cavity space. If this event occurred, the automatic cover over that particular launch chute could be prevented from closing and the cover-motor could even burn out. This left a very undesirable flight condition.